Antiplatelets and anticoagulants Flashcards
What class of drugs are clopidogrel and ticagrelor?
P2Y12 ADP receptor antagonists
How do clopidogrel and ticagrelor act?
P2Y12 receptor antagonist, prevents platelet aggregation
In what circumstances is there a preference of clopidogrel or ticagrelor?
Clopidogrel is preferred if high bleeding risk or if patient taking oral anticoagulant
What is the mechanism of action of aspirin?
Blocks cyclooxyrgenase 1 and 2, which blocks synthesis of prostaglandin, prostacyclin and thromboxane
Blocking thromboxane A2 formation prevents platelet aggregation
What is the mechanism of action of apixaban, edoxaban and rivaroxaban?
Inhibit factor XA
- factor Xa normally converts prothrombin to thrombin which then converts fibrinogen to fibrin
What is the mechanism of action of dabigatran?
Direct thrombin inhibitor
What is the reversal for dabigatran?
Idarucizumab
What is the mechanism of action of warfarin?
Inhibits epoxide reductase preventing vitamin K being reduced to active hydroquinone form
This acts as cofactor in carboxylation of factor 2, 7, 9 and 10, and protein C
What is the target INR for mechanical aortic valve?
2.5
What is the target INR for mechanical mitral valve?
3.5
What is the target INR for VTE?
2.5
Recurrent = 3.5
What is the target INR for AF?
2.5
What factors may potentiate warfarin?
Liver disease
P450 enzyme inhibitors eg ciprofloxacin, amiodarone
NSAIDs
What is the management of a patient ion warfarin with a major bleed?
IV vit K and prothrombin complex concentrate (or FFP if not available)
When should warfarin be restarted if it has been withheld for high INR?
Once INR <5
